Plant-mimicking gel could morph into any 3D shape

Instead of using a 3D printer to build up an object in layers, a single sheet of material could morph into just about any structure thanks to a new technique. Devised by Ryan Hayward and colleagues from University of Massachusetts at Amherst, it involves spreading a pattern on a responsive material to control how it deforms when exposed to a stimulus. Although, so far temperature-sensitive materials are the most advanced, the team is also looking at sheets that respond to electric and magnetic fields, as well as chemical cues.

The method is inspired by the way adjacent areas in plants can grow into different shapes. Curly edges in leaves or petals form as some cells expand, while neighbouring ones do not. To mimic this strategy, the light-sensitive gel in this video was coated with a mask to restrict the areas exposed to ultraviolet light. The amount of light absorbed by each part of the sheet determines how much it will swell when in contact with water, allowing the gel to be moulded into a specific shape. You can watch it shrink to form a flat disc when heated and then regrow into a buckled 3D shape upon cooling.

The team hopes to use the technique to create artificial blood vessels and organs. Recent studies have shown that patterned growth of thin layers of cells are often responsible for the way biological tissues and organs develop. "An area of interest for us is whether synthetic materials with patterned swelling can be used to guide shapes that cultured tissues adopt when grown in the lab," says Hayward.